The invention relates to a gas-blast switch.
The invention is of the general type that is described in the prior art Gas-blast switches, as represented for example in FIGS. 1 and 2 of DE-No. A1-33 21 740. The known switch has a housing enclosing an arcing chamber, an accumulator and an expansion space. Two relatively moveable contact members, one of which can be guided through a nozzle, are arranged in the housing. The nozzle opening is variable along its discharge cross-section. This is attained by moveable nozzle parts which are guided inward by means of compression springs when the gas-blast switch is switched off. This reduces the discharge cross-section of the nozzle at switch off and thus the pressure loss upon discharge of extinguishing gas from the accumulator or from the arcing chamber via the nozzle into the expansion space is reduced.
The invention has the object of creating a gas-blast switch in which the discharge cross-section of the nozzle is variable, independently of the action of elaborate compression springs.
The gas-blast switch according to the invention is characterized by simple design and by a nozzle whose discharge cross-section is essentially determined by the pressure conditions in the arcing chamber and in the accumulator. Elaborate compression springs are dispensed with. Furthermore, the possible occurrence of welding effects at the nozzle parts is eliminated in a simple manner.